Raschig ring

A Raschig ring is a piece of tube, approximately equal in length and diameter, used in large numbers as a packed bed within columns for distillations and other chemical engineering processes.

They are usually ceramic, metal, or glass and provide a large surface area within the volume of the column for interaction between liquid and gas vapours.

The Pall-Ring, commonly spelled as Pall ring, developed by Wilhelm Pfannmüller of BASF during the WWII,[6] attempts to increase the useful aspects of packing, by giving an increased number of edges to disrupt flow, while also reducing the volume taken up by the ring packing medium itself.

[8] The 'rings' no longer resemble rings but are pressed from metal sheet in the form of wave shapes of narrow strips.

[9] The Bialecki ring, developed by the same Pfanmüller as the Pall-Ring and first patented by him in 1944,[10] is mistakenly named after the Polish chemical engineer from Kraków Zbigniew Białecki.